UI Scale is one way, but when I'm making an addon, I can't set the users UI scale to my value.

I guess I should have been clear, I did not intend to create a standalone addon that modified the UI Scale. My whole purpose was to set my overall resolution for every addon to use, while maintaining my screen resolution so that everything looks pixel perfect and I can create my custom textures more easily. The way this should be used for addon creators is to create their addons/ui packs in a precise and realistic environment, which is in my opinion when the number of pixels you're working with is identical to your native resolution.

In fact, if I understand what you guys are doing here, I highly disapprove. It looks like you guys are making your addons ignore the UI scale... and in my opinion, this is a terrible idea! This is not what I had in mind AT ALL. Your addons should never ignore a user's UI scale. If I found one that did, I would probably promptly trash it.